Patent GB-394788-A (GB)
Title: A machine tool for drilling, tapping, screwing and like operations
IPC: B23B47/18
Filed: 1932-04-21
Abstract: 394,788. Drilling - machines; screwing; tapping. MARCHAL, P. E. A., 9, Rue Condorcet, Paris. - April 21, 1932, No. 11424. Convention date, April 22, 1931. [Class 83 (iii).] In a machine tool for drilling, tapping, screwing, and like operations of the type having a twospeed reversing drive for the toolcarrying spindle controlled by a dog clutch which is splined on the spindle and is operated by a rocking fork, the fork is pivotally connected to a turnbuckle connecting two vertically movable aligned rods of which the lower is slidably guided in a lug on the machine and the upper is spring-pressed so as to urge the dog-clutch into a position for driving the spindle in one direction while an automatically releasable locking device carried by the lower rod is adapted to hold the dog clutch against the spring action in a position for rotating the spindle in the reverse direction. The lower rod carries adjustable abutments which coact with the lug through which the rod is guided and with a trip member moving with the toolcarrying spindle to effect reversal after a stroke of predetermined length. The driving shaft 12 driven from a reversible electric motor 7, Fig. 1, through stepped pulleys 8, 9 may be coupled to the countershaft 17 by the gear wheels 15, 16, the latter being movable on the countershaft by a pivoted lever 20, Fig. 2. The ratio of the gear wheels is such that the shaft 17 rotates at higher speed than the driving shaft 12. The shafts 12, 17 carry at their ends bevel pinions 14, 23. The pinion 14 is constantly in mesh with a bevel pinion 24 integral with a sleeve 25, and a pinion 23 with a second pinion 27 integral with a sleeve 28. The sleeves 25, 28 are in axial alignment and by means of bushes 30, 31 serve as bearings for the tool-carrying spindle 5. Either of the bevel pinions 24, 27, can be positively coupled to the spindle 5 by a dog 32 slidably keyed on the spindle 5 between the bearings, and carrying claws engaging co-operating claws on the bearings 25, 28. The dog 32 is controlled by a pivoted fork 34 connected at its other end to a turn-buckle 36 carrying and connecting two vertical rods 37, 38 slidably mounted in the head casing. A spring 39 normally depresses the turnbuckle 36 so as to clutch the spindle 5 to the high-speed reversing pinion 27, but the clutch may be held in engagement with the bearing 25 by a locking device, comprising a collar 41 integral with the rod 38. One or more balls 43, Fig. 3, located in tubes 44 carried by the head casing are pressed by springs 45 into an annular groove 42 on the collar 41, the strength of the springs being adjustable by screws 46. The rod 38 is screw-threaded and carries four adjustable abutments 47 .. 50. The abutments 49, 50 engage a lug 52 formed on the machine head, the lower end of the rod 38 sliding through the lug and being terminated by a stop washer. The abutments 47, 48 are engaged by a lug 51 on a sleeve member 56 carried by the spindle 5 and moving vertically with it. The sleeve 56 has a vertical rack 57 meshing with a pinion 58 operated by a handle 59 to feed the tool, a spiral spring (not shown) mounted on the handle automatically returning the spindle 5 upwards on a release of the handle. The feed may be automatic. When the spindle has been fed down the required amount the lug 51 engages the abutment 48 and releases the collar 41 from its locked position, and the spring 39 then actuates the turn-buckle to clutch the spindle to the high-speed reverse drive. Various settings of the abutments 47 .. 50 to suit special purposes, such as drilling holes of predetermined depth are described. By reversing the electric motor 7 the high-speed drive may be employed for the forward drive of the spindle. By disengaging the gear wheels 15, 16 the machine becomes a plain drilling-machine. The mandrel 69, Fig. 12, on which the screwing die 70 is secured by screws 71 carries an external cup 72 adapted to receive lubricating- oil, the cup opening through conduits 73 into the central bore 74. The work-table 6, Fig. 1, is mounted in a sleeve 61, Fig. 4, and locked by a screw 62, the sleeve 61 being in its turn rotatable about a horizontal axis and clamped by a screw 63. A spring-pressed peg 64 in the sleeve 61 engages recesses 66 in the supporting collar 68.